Cross-Site Scripting- The Security Hole To Your Website That You Should Take Care Of!

Be it a software development company or businesses that need web applications, both struggles for the same- a robust web application that’s build in secured environment. Even, in the leading companies, separate security departments are setup that take care of application security.

Professional app development standards are followed and different type of testing like- manual code review, automated testing, unit testing, integration testing and more is done, but still, sometimes, the malicious code or scripts are able to get inside the application. Right?

The popularly known attacker that has become major headache for the developers is Cross-Site Scripting (XSS). Well, XSS is not new, but, for the novice developers, it may be, so let’s take a quick look at XSS.

Cross-Site Scripting is essentially a threat that manipulates the client-side code of web application due to the security weaknesses of client-side scripting languages, such as HTML and JavaScript. Using XSS, hackers can easily inject malicious client-side script in a website which is executed by the users. The XSS change the presentation of data in an unauthorized way and directs the browser to incorrect page or website automatically.

XSS Attacks are of Three Types:

- Persistent:

In persistence attacks, the malicious code is sent to a website where it’s stored for specific duration of time like- message board posts, web mail messages, web chat software and pretty more. It affects the web application just by viewing the web page where vulnerable code/link is sent.

- Non-persistent:

The attacker may send victim an email containing link with malicious content (JavaScript) and when victim clicks on the link, the HTTP POST request is initiated from the victim’s browser and there onwards sent to the vulnerable app automatically. Later, the malicious JavaScript appear in victim’s browser and execute in the content of victim’s user’s session.

- DOM Based: 

In such XSS attack, the data does not touch the web server, while it is reflected on JavaScript code on the client side.

This is all about how these three attackers attacks the websites in different ways. Let’s take a glance how this Cross-site Scripting actually works.

It’s very easy for the hackers to run malicious JavaScript code in a victim’s browser. What they all need is to first seek out a way to inject a metadata or messages that users frequently use to visit a web page and this can be identified with social engineering tools at ease.

When the user will visit a vulnerable page with an injected JavaScript code, the attacker needs to include user input in web pages and wherein they insert a string that’s considered as code by the victim’s browser. The attacker’s malicious script get executed as the page loads in victim’s browser in a matter of seconds.

At last, let’s see the consequences and what’s more this XSS can do with JavaScript:

- Disclosure of user session cookies

- Hijack the user’s session and sometimes, even take over the account

- Modify the presentation of Web content

- Redirect the user to vulnerable websites

- Disclosure of end user files and other documents

- Installation of Trojan horse programs

- Spread web worms

- Exploit intranet appliances and applications

What’s next?
How to protect from this malware is the next question hitting your mind? Correct? Well, you can disable such worms that’s fooling you and making your website vulnerable using HttpOnly flag. The HP Fortify tool is highly used by the developers that scan the web applications at the places where code is endangered with the attack of malwares like- XSS. Regularly, the tool enlist the points alongside description where the code is at the verge of attack, and also provide the processes to fix the security holes. Begin robust and scalable web development using advanced technology and tools!

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